feat(tracing): Add setName method on spans

[AbhiPrasad]

ref #8724

In preparation for adding the new span creation methods, startSpan and startActiveSpan, this PR adds name to spanContext. Over time we are going to be moving away from span.description, and this is the first step to get there.

For now, name is just an alias for span.description, and is only added so that users can do

const span = span.startChild({ name: 'NAME HERE' });

relatively easily.

Next steps is to add the span creators!

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser (incl. Tracing, Replay) - Webpack (gzipped)	75.12 KB (+0.36% 🔺)
@sentry/browser (incl. Tracing) - Webpack (gzipped)	31.14 KB (+0.09% 🔺)
@sentry/browser - Webpack (gzipped)	21.81 KB (0%)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (gzipped)	69.73 KB (+0.27% 🔺)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (gzipped)	28.18 KB (+0.1% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped)	20.18 KB (+0.04% 🔺)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (minified & uncompressed)	219.89 KB (+0.38% 🔺)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (minified & uncompressed)	84.78 KB (+0.13% 🔺)
@sentry/browser - ES6 CDN Bundle (minified & uncompressed)	59.86 KB (+0.04% 🔺)
@sentry/browser (incl. Tracing) - ES5 CDN Bundle (gzipped)	31.04 KB (+0.09% 🔺)
@sentry/react (incl. Tracing, Replay) - Webpack (gzipped)	65.3 KB (+0.39% 🔺)
@sentry/react - Webpack (gzipped)	21.84 KB (0%)
@sentry/nextjs Client (incl. Tracing, Replay) - Webpack (gzipped)	92.94 KB (+0.32% 🔺)
@sentry/nextjs Client - Webpack (gzipped)	50.66 KB (+0.1% 🔺)

[Lms24]

Nice!

[Lms24]

No action required: Should we think about adding span name source field? I was just thinking that in a world of #onlyspans we probably still need a way to annotate the name source, no?

[AbhiPrasad]

For now the answer is no - but we'll come back to this.